@Builder,
some simple animals and many plants can reproduce sexually AND asexually(all in the same species).
We often take vegetative "cuttings" of plant tissue all the time and many trees can propogate offspring by just spalling off parts of bark or branches. Some of the earliest gymnosperms were self fertilizing.
There are some animals that have multiple pathways of breeding such as parthenogenesis or fission.
So , even sexual reproduction, while a later entry, doesn't stop everything by not being timed right. Many times the whole thing is overcome by the organisms producing huge amounts of eggs (seed, spores,sperm etc) and "taking their chances"